Given, major ∠AOB = 260°
Minor ∠AOB = 360° - 260° = 100°
We know that radius and tangent are perpendicular. So,
∠NAO =∠NBO = 90°
In a quadrilateral NAOB,
∠NAO + ∠AOB + ∠NBO + ∠ANB = 360°
90° + 100° + 90° + ∠ANB = 360°
∠ANB = 360° - 280°
⇒∠ANB = 80°
Hence, the value of ∠ANB is 80°.